From f3dbc9dda10e52610e3de26f538b5581fd905505 Mon Sep 17 00:00:00 2001
From: sebres <serg.brester@sebres.de>
Date: Thu, 12 Dec 2019 21:28:16 +0100
Subject: [PATCH] set real thread names (used for identification and diagnostic
 purposes, e. g. top -H, ps -e -T, pstree, etc)

---
 fail2ban/helpers.py              | 24 ++++++++++++++++++++++++
 fail2ban/server/actions.py       |  2 +-
 fail2ban/server/filter.py        |  2 ++
 fail2ban/server/jailthread.py    | 15 +++++++++++++--
 fail2ban/server/server.py        |  4 +++-
 fail2ban/tests/filtertestcase.py |  2 +-
 6 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/fail2ban/helpers.py b/fail2ban/helpers.py
index c6da8f30..8d981ed6 100644
--- a/fail2ban/helpers.py
+++ b/fail2ban/helpers.py
@@ -32,6 +32,13 @@ from threading import Lock
 
 from .server.mytime import MyTime
 
+try:
+	import ctypes
+	_libcap = ctypes.CDLL('libcap.so.2')
+except:
+	_libcap = None
+
+
 PREFER_ENC = locale.getpreferredencoding()
 # correct preferred encoding if lang not set in environment:
 if PREFER_ENC.startswith('ANSI_'): # pragma: no cover
@@ -451,6 +458,23 @@ def substituteRecursiveTags(inptags, conditional='',
 	return tags
 
 
+if _libcap:
+	def prctl_set_th_name(name):
+		"""Helper to set real thread name (used for identification and diagnostic purposes).
+		"""
+		try:
+			if sys.version_info >= (3,): # pragma: 2.x no cover
+				name = name.encode()
+			else: # pragma: 3.x no cover
+				name = bytes(name)
+			_libcap.prctl(15, name[0:15]) # PR_SET_NAME = 15, name can be up to 15 bytes long (16 bytes with NTS zero)
+		except:
+			pass
+else: # pragma: no cover
+	def prctl_set_th_name(name):
+		pass
+
+
 class BgService(object):
 	"""Background servicing
 
diff --git a/fail2ban/server/actions.py b/fail2ban/server/actions.py
index 1090fed0..51904ecd 100644
--- a/fail2ban/server/actions.py
+++ b/fail2ban/server/actions.py
@@ -75,7 +75,7 @@ class Actions(JailThread, Mapping):
 	"""
 
 	def __init__(self, jail):
-		JailThread.__init__(self)
+		JailThread.__init__(self, name="f2b/a."+jail.name)
 		## The jail which contains this action.
 		self._jail = jail
 		self._actions = OrderedDict()
diff --git a/fail2ban/server/filter.py b/fail2ban/server/filter.py
index 94342b31..98c28e35 100644
--- a/fail2ban/server/filter.py
+++ b/fail2ban/server/filter.py
@@ -109,6 +109,8 @@ class Filter(JailThread):
 		self.checkFindTime = True
 		## Ticks counter
 		self.ticks = 0
+		## Thread name:
+		self.name="f2b/f."+self.jailName
 
 		self.dateDetector = DateDetector()
 		logSys.debug("Created %s", self)
diff --git a/fail2ban/server/jailthread.py b/fail2ban/server/jailthread.py
index 5c7afd38..d0430367 100644
--- a/fail2ban/server/jailthread.py
+++ b/fail2ban/server/jailthread.py
@@ -29,7 +29,7 @@ from threading import Thread
 from abc import abstractmethod
 
 from .utils import Utils
-from ..helpers import excepthook
+from ..helpers import excepthook, prctl_set_th_name
 
 
 class JailThread(Thread):
@@ -76,6 +76,15 @@ class JailThread(Thread):
 					print(e)
 		self.run = run_with_except_hook
 
+	if sys.version_info >= (3,): # pragma: 2.x no cover
+		def _bootstrap(self):
+			prctl_set_th_name(self.name)
+			return super(JailThread, self)._bootstrap();
+	else: # pragma: 3.x no cover
+		def __bootstrap(self):
+			prctl_set_th_name(self.name)
+			return Thread._Thread__bootstrap(self)
+
 	@abstractmethod
 	def status(self, flavor="basic"): # pragma: no cover - abstract
 		"""Abstract - Should provide status information.
@@ -108,4 +117,6 @@ class JailThread(Thread):
 		if self.active is not None:
 			super(JailThread, self).join()
 
-
+## python 2.x replace binding of private __bootstrap method:
+if sys.version_info < (3,): # pragma: 3.x no cover
+	JailThread._Thread__bootstrap = JailThread._JailThread__bootstrap
diff --git a/fail2ban/server/server.py b/fail2ban/server/server.py
index 35f966e8..7c820e49 100644
--- a/fail2ban/server/server.py
+++ b/fail2ban/server/server.py
@@ -38,7 +38,7 @@ from .transmitter import Transmitter
 from .asyncserver import AsyncServer, AsyncServerException
 from .. import version
 from ..helpers import getLogger, _as_bool, extractOptions, str2LogLevel, \
-	getVerbosityFormat, excepthook
+	getVerbosityFormat, excepthook, prctl_set_th_name
 
 # Gets the instance of the logger.
 logSys = getLogger(__name__)
@@ -80,6 +80,8 @@ class Server:
 			'Linux': '/dev/log',
 		}
 		self.__prev_signals = {}
+		# replace real thread name with short process name (for top/ps/pstree or diagnostic):
+		prctl_set_th_name('f2b/server')
 
 	def __sigTERMhandler(self, signum, frame): # pragma: no cover - indirect tested
 		logSys.debug("Caught signal %d. Exiting", signum)
diff --git a/fail2ban/tests/filtertestcase.py b/fail2ban/tests/filtertestcase.py
index 38d77d0b..41a6f0bf 100644
--- a/fail2ban/tests/filtertestcase.py
+++ b/fail2ban/tests/filtertestcase.py
@@ -266,7 +266,7 @@ class BasicFilter(unittest.TestCase):
 
 	def setUp(self):
 		super(BasicFilter, self).setUp()
-		self.filter = Filter('name')
+		self.filter = Filter(None)
 
 	def testGetSetUseDNS(self):
 		# default is warn